breathing control Flashcards
What are the three main types of pulmonary mechanoreceptors and two main types of chemoreceptors>
Slowly Adapting Stretch Receptors (SAR or PSR), Irritant or Rapidly Adapting Stretch (RAR), C-fibers——–Peripheral (carotid,aortic) and central
PSR: location, description, what activates them, what they do
Airway SM; myelinated fibers in vagus nerve; lung inflation or bronchoconstriction; 3 results 1)Breuer-hering reflex 2)abdominal muscle activation 3)Bronchodilation neg feedback loop
Breuer-Hering Reflex
activated by PSR. Facilitates expiration by terminating inspiration when V(T) is 3 x normal and prolonging expiration when elevated lung volume is maintained during expiration (obstruction)
Regulation of respiratory muscle activity is ____ not ____
automatic not autonomic
RAR: what stimulates, location, result of activation
inhaled irritants and rapid large inflation; b/w airway epithelial cells; protective reflexes such as cough/sneeze, bronchoconstriction and shallow rapid breathing
C-fibers: location, stimulation, effect
In close proximity to alveoli and w/in airway epithelium; edema and irritants; rapid shallow breathing, sensation of breathlessness; activated in LV failure, pneumonia, PE
peripheral chemoreceptors: location, stimulation, effect
carotid and aortic; decreased PaO2 (not O2 content), increased PaCO2, decreased pHa; not much response until PaO2<90)
why wont the peripheral chemoreceptors be directly stimulated in anemia, CO poisoning
b/c the PO2 will be normal i those cases and they sense content
Central chemoreceptors: location, stimulus
retrotrapezoid nucleus in medulla; increase in PaCO2 or decrease in pHa but not to changes in PaO2
Are central chemoreceptors more responsive to PaCO2 or pHa changes? Why? How sensitive is it?
PaCO2. The BBB is impermeable to H+. Ventilation can double with a 2mmHg increase.
which exerts are larger effect on ventilation, central or peripheral chemoreceptors?
central by far
Describe the relationship of change in V(dot)A with PaCO2. The change in PaCO2 with V(dot)A.
Linear. Hyperbolic (as described by alveolar ventilation equation)
overall ventilatory response to PCO2 and PO2
response to hypercapnia augments response to hypoxia and vice versa
what produces the respiratory stimulus? how is the sensory input involved?
a central pattern generator (CPG). Phasic sensory input may modify but is not essential for the basic pattern
Describe the respiratory neuroanatomy
three bilaterally symmetric groups: Dorsal respiratory Group (DRG), Ventral Respiratory Column (VRC), and Pontine Respiratory Group (PRG)
